AIR applications are distributed via
AIR installer files which use the
air
extension or
via native installers, which use the file format and extension of
the native platform. For example, the native installer format of
Windows is an EXE file, and for Android the native format is an
APK file.
When Adobe AIR is installed and an AIR installer file is opened,
the AIR runtime administers the installation process. When a native
installer is used, the operating system administers the installation
process.
Note:
Developers can specify a version, and application
name, and a publisher source, but the initial application installation
workflow itself cannot be modified. This restriction is advantageous
for users because all AIR applications share a secure, streamlined,
and consistent installation procedure administered by the runtime.
If application customization is necessary, it can be provided when
the application is first executed.
Runtime installation location
AIR applications first require the runtime to be installed on
a user's computer, just as SWF files first require the Flash Player
browser plug-in to be installed.
The runtime is installed to the following location on desktop
computers:
On
Mac OS, to install an updated version of an application, the user
must have adequate system privileges to install to the application
directory. On Windows and Linux, a user must have administrative
privileges.
Note:
On iOS, the AIR runtime is not installed separately; every
AIR app is a self-contained application.
The runtime can be installed in two ways: using the seamless
install feature (installing directly from a web browser) or via
a manual install.
Seamless install (runtime and application)
The seamless install feature provides developers with a streamlined
installation experience for users who do not have Adobe AIR installed
yet. In the seamless install method, the developer creates a SWF
file that presents the application for installation. When a user
clicks in the SWF file to install the application, the SWF file
attempts to detect the runtime. If the runtime cannot be detected
it is installed, and the runtime is activated immediately with the
installation process for the developer's application.
Manual install
Alternatively, the user can manually download and install the
runtime before opening an AIR file. The developer can then distribute
an AIR file by different means (for instance, via e-mail or an HTML
link on a website). When the AIR file is opened, the runtime begins
to process the application installation.
Application installation flow
The AIR security model allows users to decide whether to install
an AIR application. The AIR install experience provides several
improvements over native application install technologies that make
this trust decision easier for users:
-
The runtime provides a consistent installation experience
on all operating systems, even when an AIR application is installed
from a link in a web browser. Most native application install experiences
depend upon the browser or other application to provide security
information, if it is provided at all.
-
The AIR application install experience identifies the source
of the application and information about what privileges are available
to the application (if the user allows the installation to proceed).
-
The runtime administers the installation process of an AIR
application. An AIR application cannot manipulate the installation
process the runtime uses.
In general, users should not install any desktop application
that comes from a source that they do not trust, or that cannot
be verified. The burden of proof on security for native applications
is equally true for AIR applications as it is for other installable
applications.
Application destination
The installation directory can be set using one of the following
two options:
-
The user customizes the destination during installation.
The application installs to wherever the user specifies.
-
If the user does not change the install destination, the
application installs to the default path as determined by the runtime:
If the developer specifies an
installFolder
setting
in the application descriptor file, the application is installed
to a subpath of this directory.
The AIR file system
The install process for AIR applications copies all files that
the developer has included within the AIR installer file onto the
user's local computer. The installed application is composed of:
-
Windows: A directory containing all files included in
the AIR installer file. The runtime also creates an exe file during
the installation of the AIR application.
-
Linux: A directory containing all files included in the AIR
installer file. The runtime also creates a bin file during the installation
of the AIR application.
-
Mac OS: An
app
file that contains all of
the contents of the AIR installer file. It can be inspected using
the "Show Package Contents" option in Finder. The runtime creates
this app file as part of the installation of the AIR application.
An AIR application is run by:
-
Windows: Running the .exe file in the install folder,
or a shortcut that corresponds to this file (such as a shortcut
on the Start Menu or desktop).
-
Linux: Launching the .bin file in the install folder, choosing
the application from the Applications menu, or running from an alias
or desktop shortcut.
-
Mac OS: Running the .app file or an alias that points to
it.
The application file system also includes subdirectories related
to the function of the application. For example, information written
to encrypted local storage is saved to a subdirectory in a directory
named after the application identifier of the application.
AIR application storage
AIR applications have privileges to write
to any location on the user's hard drive; however, developers are
encouraged to use the
app-storage:/
path for local storage
related to their application. Files written to
app-storage:/
from
an application are located in a standard location depending on the
user's operating system:
-
On Mac OS: the storage directory of an application is
<appData>/<appId>/Local Store/
where
<appData>
is the user's “preferences
folder,” typically:
/Users/<user>/Library/Preferences
-
On Windows: the storage directory of an application is
<appData>\<appId>\Local Store\
where
<appData>
is
the user's CSIDL_APPDATA “Special Folder,” typically:
C:\Documents and Settings\<user>\Application Data
-
On Linux:
<appData>/<appID>/Local Store/
where
<appData>
is
/home/<user>/.appdata
You can access the application storage directory via the
air.File.applicationStorageDirectory
property.
You can access its contents using the
resolvePath()
method
of the File class. For details, see
Working with the file system
.
Updating Adobe AIR
When the user installs an AIR application that requires an updated
version of the runtime, the runtime automatically installs the required
runtime update.
To update the runtime, a user must have administrative privileges
for the computer.
Updating AIR applications
Development and deployment of software updates are one of the
biggest security challenges facing native code applications. The
AIR API provides a mechanism to improve this: the
Updater.update()
method
can be invoked upon launch to check a remote location for an AIR
file. If an update is appropriate, the AIR file is downloaded, installed,
and the application restarts. Developers can use this class not
only to provide new functionality but also respond to potential security
vulnerabilities.
The Updater class can only be used to update applications distributed
as AIR files. Applications distributed as native applications must
use the update facilities, if any, of the native operating system.
Note:
Developers can specify the version of an application
by setting the versionNumber property of the application descriptor
file.
Uninstalling an AIR application
Removing an AIR application removes
all files in the application directory. However, it does not remove
all files that the application may have written to outside of the
application directory. Removing AIR applications does not revert changes
the AIR application has made to files outside of the application directory.
Windows registry settings for administrators
On Windows, administrators can
configure a machine to prevent (or allow) AIR application installation
and runtime updates. These settings are contained in the Windows
registry under the following key: HKLM\Software\Policies\Adobe\AIR. They
include the following:
Registry setting
|
Description
|
AppInstallDisabled
|
Specifies that AIR application installation
and uninstallation are allowed. Set to 0 for “allowed,” set to 1 for
“disallowed.”
|
UntrustedAppInstallDisabled
|
Specifies that installation of untrusted
AIR applications (applications that do not includes a trusted certificate)
is allowed. Set to 0 for “allowed,” set to 1 for “disallowed.”
|
UpdateDisabled
|
Specifies that updating the runtime is allowed,
either as a background task or as part of an explicit installation.
Set to 0 for “allowed,” set to 1 for “disallowed.”
|
|
|
|